Factors / Factors of 63

Factors of 63

1, 3, 7, 9, 21, 63

63 breaks into 3 pairs, tested up to √63 ≈ 7.9; each pair multiplies back to 63 exactly. 63's full pair list is (1, 63), (3, 21), (7, 9), for 6 divisors in total. 63's divisors other than 63 itself sum to just 41, 22 below 63: the common deficient case. 63 is odd, digit sum 9 for 63; small divisors of 63 include 3, 7, 9. 63 has 6 divisors; 62 has 4 and 64 has 7, so 64 wins here. 63 divided by its largest divisor, 21, gives 3.